A new Cornell study found satellite imagery can help land managers track European spongy moth damage and identify where surveillance or insecticide treatment may be needed.
Researchers developed an algorithm that detects rapid changes in forest canopies as moth larvae strip leaves and deciduous trees later regrow them, according to findings published in Forest Ecology and Management.
Spongy moth damage can be difficult to monitor from the ground because outbreaks appear in scattered areas and change quickly early in the growing season. The satellite-based method uses a series of images from the European Space Agency's Sentinel-2 satellite to create a defoliation index.
The study also found evidence that warm, dry summers may precede larger outbreaks the following year. Pathogens that kill spongy moth larvae need moisture, so more larvae may survive to lay eggs when conditions are dry, researchers said.
The moths feed on about 300 tree species. Deciduous trees can often regrow leaves after caterpillars move on, but conifers and evergreens are less able to replace lost foliage and face higher mortality during severe outbreaks.
Cameron Scholl, a doctoral student and the study's first author, said better risk maps could help land managers focus spring searches for egg masses and larvae across large areas.
The study was led by Cornell researchers and supported by the Cornell Atkinson Center for Sustainability and the U.S. Department of Energy.
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